1. Field of the Invention
The present invention relates to a display apparatus, and more particularly, to a liquid crystal display and a method for manufacturing the same.
2. Discussion of the Related Art
In a related art liquid crystal display device, a liquid crystal layer having an anisotropic dielectric constant characteristic is formed between an upper substrate and a lower substrate. When an electric filed is applied to the liquid crystal layer, the molecular arrangement of a liquid crystal material is changed, thereby controlling the amount of light transmit through the upper substrate and a desired image is displayed. The related art liquid crystal display devices include a thin film transistor-liquid crystal display (TFL-LCD) display using a TFT as a switching device.
The related art TFT LCD device uses an electro-optical characteristic of the liquid crystal material to control light transmit through the upper substrate. The electro-optical characteristic of the liquid crystal material is determined by anisotropy of liquid crystal material and a state of molecular orientation of the liquid crystal material. Accordingly, it is important to control the molecular orientation of the liquid crystal material by forming an orientation film on the upper and lower substrates. The orientation films align the liquid crystal material, thereby improving the quality of images. When aligning the orientation film, a rubbing method is mainly used. In the related art rubbing method, the orientation film made of polyamide material is formed on the upper and lower substrates and a rubbing roll is applied to the orientation film.
In recent years, such related art rubbing method may have reached its limit because it became difficult to finely adjusting a variety of process variables while aligning the molecular orientation of the liquid crystal material. In addition, it has become difficult to prevent the generation of electrostatic. Thus, photo alignment, ion beam alignment, and other suitable alignment method have been studied to eliminate the use of the related art alignment film (hence, promotes no physical contact while controlling the molecular orientation of the liquid crystal material).
However, in related art non-contact alignment method, such as the photo alignment method and the ion beam alignment method, productivity of the liquid crystal display device becomes low because the manufacturing process becomes difficult. In addition, no substitute material to the related art alignment film has been developed in the non-contact alignment method. Accordingly, there is a continuous demand for developing equipment that produces more effective alignment process and alignment materials that optimize the alignment process.
In addition, the related art non-contact alignment method using a shear force includes the method using a magnetic field and an electric field. In the above discussed related art non-contact alignment methods, the liquid crystal material interacts with each other by the external force exerted by the photo process and the ion beam process or the external magnetic field and the electric field, thereby forming the initial alignment. In these related art alignment method, the liquid crystal material directly contacts the substrate since no orientation film is used. Accordingly, the alignment anchoring force is minimized or eliminated, but in either case, it acts very weakly.
As such, in the related art non-contact alignment methods, the alignment anchoring force does not work properly. In other words, even when the liquid crystal material is aligned at the desired direction initially, the force that allows the liquid crystal material to return to the initial alignment state after the orientation of the liquid crystal material is changed does not work properly, thereby deteriorating the orientation resilience.